1,120. If Grain Becomes Wet

Chometz u’Matzah 5:9

Exodus 12:17 tells us to “guard the matzos,” meaning that we must be mindful of them and not permit them to become chometz. The Sages said that one must be careful about the grain he eats on Passover that no water has come in contact with it after harvesting, to keep it from leavening. If grain fell in a river or otherwise came in contact with water, just as one may not eat it on Passover, so may he not possess it. If he sells it to a Jew, he must tell him what happened so that he can eat it before Passover. If he sells it to a non-Jew before Passover, he should sell a small quantity to several different people so that it will be finished before Passover. This keeps the non-Jew from re-selling it to a Jew.

Chometz u’Matzah 5:10

If rainwater leaked onto grain, as long as it continues to drip onto it, it will not become chometz – not even if this goes on all day. However, once if stops, if it sits for the prescribed duration, it becomes chometz.